1. Field of the Invention
The present invention relates to an imaging device and an imaging system.
2. Description of the Related Art
Reducing power consumption is one issue for conventional imaging devices. In an imaging device driven by a rechargeable battery, this issue is highly important because the power consumption of the device affects the shooting time or number of images captured per battery charging. There are also other issues such as increasing the number of pixels in a solid-state image sensor and increasing the frame rate (increasing the readout rate). Improving the operating frequency of readout from solid-state image sensors for high-speed readout is followed by an increase in power consumption, and thus reducing power consumption and improving the frame rate are the conflicting issues. In the solid-state imaging device disclosed in Japanese Patent Laid-Open No. 2008-283331, in order to cope with both of the issues, the readout of pixel values from solid-state image sensors is shared and performed by a plurality of channels. This enables simultaneous readout of a plurality of pixels, thus allowing the device to be adapted to high-speed readout. Power consumption is further reduced by reducing the number of channels to be used for readout from solid-state image sensors, depending on the operation mode.